[7.3] Story: Create Migration Guide

[adriancofie]

Description

Document how to migrate from local components to shared library.

Parent Issue: #EPIC_7

Sub-Tasks

• Write step-by-step migration process
• Create prop API mapping tables
• Document common issues and solutions
• Add before/after code examples
• Include per-app specific notes

Notes

• See detailed Pager example in SHARED_COMPONENT_LIBRARY_PLAN.md